I use the same oil year round on everything-5-30 Mobil 1, as recommended by Briggs. I only stock one oil for everything that way. Instead of 30 wt in the lawn mower in summer and switch to 5-30 in the winter. I just use the same oil so regardless of what the temp is, I’m OK. Its down to 32 degrees here today and leaves are still coming down that will need to be dealt with. Last year I was mulching leaves in December and it was cold. I don’t have to worry about what oil I have in the lawn tractor and don’t have to have two or three oils on hand, especially since name brand 30 wt is not on the shelf anymore. That’s what I do. What anyone else does is up to them. The discussion started by asking about availability of 30 weight. I also use fuel treatment year round in everything and non-oxy gas.